Most commercially available fluorinated surfactants are produced through electrochemical fluorination, telomerization, and oligomerization. Electrochemical fluorination utilizes anhydrous hydrofluoric acid as the fluorine source. However, industrially produced hydrofluoric acid contains impurities, which requires further complicated methods to remove these impurities.
Telomerization or oligomerization processes use tetrafluoroethylene as the starting material. However, the source of available tetrafluoroethylene is limited. The product obtained from a telomerization process usually contains a mixture of homologs having different carbon chain lengths resulting in telomers with a distribution of carbon chain lengths. Therefore, the sequential separation of telomerization products is required in order to produce fluorosurfactants which contain a fixed length of the fluorinated carbon chain, as described by Erik Kissa in “Fluorinated Surfactants, Synthesis-Properties-Applications” Surfactant Science Series, Vol. 50, Marcel Dekker, New York, (1994).
U.S. Patent Application 20050127322 describes a hydrofluoroether heat transfer fluid which is represented by the following structure: Rf—O—Rh—O Rf′ wherein Rh is independently an alkylene group having from 2 to about 8 carbon atoms and at least 4 hydrogen atoms. The syntheses described in the examples of above patent application show these materials to be water insoluble; therefore, they are not suitable as surfactants.
It is desirable to have a composition comprising fluorinated surfactants which can be produced from starting materials other than tetrafluoroethylene. It is also desirable to have a method of lower surface tension using a very low concentration of surfactant, and to provide surface effects. The present invention provides such a composition comprising fluorinated nonionic surfactants which are produced from reacting fluoroalkyl vinyl ether with polyethylene glycol. The present invention also provides methods of providing surface effects to various liquids